


Second Born

by drelfina



Category: Naruto
Genre: Founders Era, Incest incest up the wazoo, M/M, Skipping straight from manual masturbation 101 to Frotting and then it's OFF TO THE RACES, also explicit porn but also not really, delayed interval delivery, i'm going to hell and i'm taking you with me, kawarama is definitely happy to flaunt his bigger size all over the place, manual masturbation 101, mentions of Itama and Hashirama, not serious fic at all sorry, shota too, young teen sexual exploration
Language: English
Status: Completed
Published: 2019-11-13
Updated: 2019-11-13
Packaged: 2021-01-30 03:51:16
Rating: Mature
Warnings: Underage
Chapters: 1
Words: 1,778
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/21421732
Author URL: https://archiveofourown.org/users/drelfina/pseuds/drelfina
Summary: Kawarama was born second. Weeks after Tobirama was, oddly enough. The midwife said she'd never seen this sort of twin before.Kawarama hit all the milestones before Tobirama did, growing up. Running, talking, jutsu.That includes puberty too.
Relationships: Senju Tobirama/Senju Kawarama
Comments: 154
Kudos: 87





	Second Born

**Author's Note:**

  * For [Perelka_L](https://archiveofourown.org/users/Perelka_L/gifts), [ValidAsshole](https://archiveofourown.org/users/ValidAsshole/gifts).

> thanks to Perelka_L and ValidAsshole for the discussion. :D

He was born second. Never saw that sort of twin before, the midwife had said, but then she was relatively young. 

Twins always came early, small and just a little weaker, so when their mother was so huge at six months, they all knew it was coming. 

Her going into labour at just two days over 8 months was terrifying, and everyone was afraid she'd lose them. 

Instead, just one was born.

He stayed in the womb, oddly enough, while his brother was taken, thin and pale and almost as transparent as glass, into the medics hall, to be cared for .

Kawarama, on the other hand, apparently refused to leave the warmth of his mother's womb, staying for another three weeks to be born screaming enough for two.

So while they were twins, Tobirama was older by three weeks, sickly for almost a year, and Kawarama was born strong and hale. 

For a long time of their childhood, Kawarama slammed into childhood checkpoints at full speed while Tobirama was always a little thinner, a little shorter. That wasn't even counting the fact that he couldn't be let out of the house without being covered up entirely. 

Was it any real surprise that hashirama was closer to Kawarama than Tobirama?

Kawarama got along perfectly with their Anija. He was loud, running after Hashirama even before he could walk, perfectly happy to barrel into obstacles and blast through them to get to where Anija was going. 

His older twin would instead stay in the shade, having taught himself to read at two, and would be the one watching the new baby while Kawarama and Hashirama destroyed half the training grounds.

But Tobirama was still his twin. For all that he and hashirama shared the same sense of humour, Kawarama and Tobirama still shared the same bedroom.

"You're so hot," Tobirama would complain, whenever Kawarama flopped onto him after his bath, after a day of smashing up the training grounds. It was never boring, training, though at least no one asked him to put it back together; Kawarama's control wasn't as fine as an adult's, and unlike his twin, Kawarama had hashirama's blinding smile and winsome charm. 

"Well you're cold," Kawarama would say, peaceably, and stick his hands down Tobirama's yukata just to hear him shriek.

They were opposites; Kawarama the very image of his father, Tobirama that of their mother, and Kawarama ran hot and fast while Tobirama was cold and quiet. It wasn't a surprise that they still got along at night.

They fit. 

Tobirama was still smaller than him for all that he was supposedly older, and while he had pointy elbows it was always easy to pin him down and cuddle him just like hashirama would do.

"I'm not cold you're just way hot everyone is cold in comparison. Get off me," Tobirama would grumble. 

And yet Kawarama would just pin him and five minutes later Tobirama would stop pouting about it. 

(He was definitely colder than Kawarama. So there.)

They shared everything, though sometimes Kawarama would tease Tobirama that hed always be taller than him, that he should share clothes with ita-chan instead, because Tobirama sometimes looked like he was swimming in Kawarama's yukata when Kawarama absconded with Tobirama's without checking.

In all things physical, Kawarama hit milestones faster than Tobirama. 

Running, talking... chakra use...

And puberty.

* * *

"What are you doing?" Tobirama asked, grouchy and sleepy. He'd gone to sleep, Kawarama sprawled over him as usual, and now… 

"'M not doing anything," Kawarama said. He wasn't. Well not much really, but part of him had gotten… weird and hard and when he squirmed in the middle of the night against Tobirama's hip, it had felt… Good. 

Really good. 

"Go to _sleep_," Tobirama grouched, fingers twitching in a vague attempt to bat at Kawarama's face. 

"Gonna, am sleeping, you just stay still." 

And … Tobirama obediently went back to sleep - and even so, he was deliciously cool against the heated warmth of… well. That part. 

And squirming against his twin until that feeling - climbed and rose and _swelled_ then _popped_? 

That made Kawarama very comfortable and sleepy. 

Somehow, though, in the morning, Tobirama got really mad about his sleep clothes being sticky.

* * *

It became routine - in the daytime Kawarama trained with Hashirama, snuck into listen in on mission briefings while Tobirama read and sat in with Father for war-planning and strategizing, sometimes with Ita-chan in his lap - and night-time had Kawarama wrestling his older twin into position as his pillow and then sleeping for a few hours… before waking up in the middle of the night to his dick hard and needy. 

And Tobirama was still always cool and very nice to rock against; after the first few times, he'd gotten used to Kawarama fidgeting and used his considerable will power to ignore Kawarama and gone back to sleep, so of course Kawarama wasn't going to stop. 

Then one evening Tobirama smacked a book into Kawarama's face before he could sprawl onto Tobirama's futon. 

"Why are you - _ejaculating_ all over me at night?" Tobirama snapped. 

"Huh?" if Kawarama looked dumb enough, Tobirama would explain when he used big words. 

"I keep waking up with sticky clothes," Tobirama said, crossly. "And then when Sakao-san found me washing my laundry in the morning, she _laughed_ at me and said it's 'part of growing up'. So i had to go find a book and figure out what she meant and YOU were the one ejaculating! On me!" 

"What's 'ejaculating," Kawarama said after a moment. 

"Read the book!" Tobirama snapped. "And leave me alone!"

* * *

THe book was enlightening. Even if he had to pester Tobirama every five words or so. It was worth it to see Tobirama's ears go pink though. 

"Sooo you wanna try it?" Kawarama said. 

"Try what?" 

"Manual Masturbating," Kawarama sounded out, carefully, watching Tobirama's cheeks go pink. "But then you probably aren't even THERE yet, so I guess -" 

"If it'd get you to leave my clothes alone," Tobirama growled, "I'll do it!" 

Which was how they ended up kneeling on the futon facing each other (it'd taken five or more minutes of scuffling and Tobirama kneeing Kawaram in the hip and thighs before they settled on this position, but Kawarama was going to get Tobirama in his lap next time. He'd seen the _pictures_, and he _knew_ that Tobirama had definitely seen them too. It would of course be more fitting for _Tobirama_ to be in _his_ lap but he'd have to wait till Tobirama was half asleep and couldn't elbow him in the kidneys.) 

"You have to get your pants off," Kawarama said reasonably. "And that way you won't have to wash it tomorrow!" 

"I know that!" Tobirama said, and pulled his pants off and it wasn't like he hadn't seen his twin naked before, but this time knowing that he was going to touch his twin's cock and get him to be all hard and stuff like in the pictures? That made it look very different all of a sudden. 

And Tobirama clearly knew it too, because he was red in the face and glaring at Kawarama's pants. "You have to take yours off too." 

"Yeah yeah-" and Kawarama had no shame at all. He was bigger _all over_ than Tobirama after all, and they said that bigger was better for men, right? So he was bigger so he was _better_, and Tobirama definitely knew _that_; his ears had gone pinker. 

Then Kawarama was reaching over to firmly grasp his hand over Tobirama's cock, and Tobirama hissed, jerking backwards. "What did you do, stick your hand in fire chakra?" Tobirama yelped. 

"You're the one who stuck his dick in ice water," Kawarama retorted, "You're supposed to do the same, like in the book!" 

Tobirama glared at him, and then wrapped _his_ hand over Kawarama's cock, in retaliation. 

It felt GOOD though. Better than his own hand, better than when he had rubbed it against Tobirama's cotton-clothed hip. 

Tobirama tipped his chin up challengingly at Kawarama, so that meant Kawarama had to raise the stakes, and so he tightened his grip just enough that when he tried moving it, it made Tobirama hiss again. 

"You need to use some sort of lubricant," Tobirama complained. 

"Oh yeah? Like what? Oil?" 

Tobirama glared at him, and he let go (nooooo, Kawarama thought) to flash through some seals and then his hands were wet when they returned to Kawarama's dick. "Like _this_." 

Slick, wet, chilled, Tobirama's hand suddenly was like some sort of gliding friction-y thing on his cock, and Kawarama had to buck up into Tobirama's fist. "Hnnng!" 

"See?" Tobirama said smugly, as Kawarama felt himself harden. "That's how to do it properly - " 

"I'll show _you_ properly," Kawarama said and jolted forward fumbling to pull Tobirama almost into his lap just so he could grind his now super wet dick against Tobirama's. 

Smirked hugely when Tobirama squeaked. 

"See?" 

And Kawarama had _lots_ of practice rocking his hips - Tobirama quickly lost track of how to use his hand, since Kawarama could grab them both in _his_ hand, trapping Tobirama's fingers against both of them, all wet and slippery. Which, Kawarama had to admit, felt way better than rubbing against Tobirama's hip. They should do this all the time now. 

Tobirama made a little strangled noise, and his cock definitely got hard too. 

It was easy enough to keep doing that, pushing and tugging at both their hands and their cocks, catching hold of Tobirama's hip to hold him still so Kawarama could grind firmer - and yes, that _felt_ even better, and he was definitely hotter now, feeling the - familiar sensation tighten in his belly and thighs even faster than before, while Tobirama seemed to have lost the ability to use words. 

When that familiar feeling crested in a climax, it was huge, bigger than before, it felt like, and Tobirama yelped when the hot wetness erupted from Kawarama onto Tobirama's belly. 

"And that's how you do the masturbation," Kawarama said smugly, while Tobirama glared at him. 

"So now you're gonna leave my pants alone." 

"Of course," Kawarama said. "Cause we could do this every night instead. Or.." 

Tobirama frowned. "Or what?" 

Kawarama wiped his hand on Tobirama's belly, grinning while Tobirama growled and tried to kick him. It didn't succeed because Kawarama was awesome and also Tobirama was too close to get his legs back out from under him, so it was easy enough to haul Tobirama in against his lap. 

In answer, Tobirama wiped his sticky belly on Kawarama's hip. 

"Hey!" 

"Serve you right!" 

Brat! Well Kawarama was going to do the _next_ chapter tonight then. 

_Digital Stimulation_. 

END

**Author's Note:**

> Kawarama skipped straight over Manual Masturbation 101 to _Frotting, your dick and theirs_, and then off to DIGITAL STIMULATION 103
> 
> ** Omake 01 **
> 
> "How come you… wait you kept ejaculating on me - why weren't YOU caught cleaning the laundry?!" 
> 
> "I just put my clothes in your pile, and let them wash it." 
> 
> ** Omake 2:  **
> 
> "What - what - what are you putting in my - are those your FINGERS?!" 
> 
> "What, that's chapter 3! Digital stimulation -" 
> 
> "We haven't even finished chapter 1!" 
> 
> "That was boring, I want to skip to the fun parts!"
> 
> * * *
> 
> NOTES FOR REAL
> 
> Delayed interval birth or delivery is a real thing - but usually in most cases the delayed twin would be only a few days difference if this happens. A few hours or minutes doesn't count. But because twins or multiples have a much higher chance of being delivered prematurely, the longer they can stay in the womb the better their chances of survival. I chose to use just over 32 weeks for Tobirama's birth - it's roughly the time that premature twins can still survive without modern NICU, and Kawarama being delivered at week 35/36 is almost full-term after he booted out his twin. In real life modern medicine, such a long delay is very rare, and genrally seen only in very specific circumstances and with drug aid. We can go with Medical Chakra in this case that kept Kawarama in the womb. The twins are fraternal twins (They don't share a placenta), and the mother stopped contractions after Tobirama's birth, so that aided keeping Kawarama in. 
> 
> You can tell I did a Lot Of Research for this. 
> 
> It's mainly for the hilarity of "yeah Tobirama is technically older because he was born first by a few weeks but man is he FRAIL compared to Kawa…" 
> 
> Also, of course Tobirama would find the most scientific, driest books on puberty ever. 
> 
> Tobirama and Kawarama actually wouldn't be that much different in terms of size by the time they're toddlers at least, but Kawarama would never let Tobirama live it down GG.


End file.
